Work Energy And Power Question 230

Question: A force acts on a 30gm particle in such a way that the position of the particle as a function of time is given by x=3t4t2+t3 , where x is in metres and t is in seconds. The work done during the first 4 seconds is

Options:

A) 576mJ

B) 450mJ

C) 490mJ

D) 530mJ

Show Answer

Answer:

Correct Answer: A

Solution:

[a] x=3t4t2+t3=dxdt=38t+3t2

Acceleration =d2xdt2=8+6t

Acceleration after 4sec=8+6×4=16ms2

Displacement in 4sec=3×44×42+43=12m

Work = Force × displacement =Mass×acc.×disp.=3×103×16×12=576mJ



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